int pass_len = 0, salt_len = 0, fn;
    int iklen, ivlen, iter = 1;
    unsigned char *pass = NULL, *salt = NULL;
    const EVP_MD *md = NULL;
    const EVP_CIPHER *cipher = NULL;
    int buf_len = (EVP_MAX_KEY_LENGTH + EVP_MAX_IV_LENGTH)*4, dk_len = buf_len;
    unsigned char tmpkeyiv[(EVP_MAX_KEY_LENGTH + EVP_MAX_IV_LENGTH)*4];
    (void) clientData;

    dprintf("Called");

    /* Clear errors */
    Tcl_ResetResult(interp);
    ERR_clear_error();

	LAPPEND_BARRAY(interp, resultObj, "iv", tmpkeyiv+iklen, ivlen);
	Tcl_SetObjResult(interp, resultObj);
    }

    /* Clear data */
    memset(tmpkeyiv, 0, buf_len);
    return TCL_OK;

}

/*
 *-------------------------------------------------------------------
 *
 * KDF_HKDF --
 *

    EVP_PKEY_CTX *pctx = NULL;
    const EVP_MD *md = NULL;
    unsigned char *salt = NULL, *key = NULL, *info = NULL, *out = NULL;
    int salt_len = 0, key_len = 0, info_len = 0, res = TCL_OK, fn;
    int dk_len = EVP_MAX_KEY_LENGTH + EVP_MAX_IV_LENGTH;
    size_t out_len;
    Tcl_Obj *resultObj;
    (void) clientData;

    dprintf("Called");

    /* Clear errors */
    Tcl_ResetResult(interp);
    ERR_clear_error();

static int KDF_Scrypt(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]) {
    EVP_PKEY_CTX *pctx = NULL;
    unsigned char *salt = NULL, *pass = NULL, *out = NULL;
    int salt_len = 0, pass_len = 0, dk_len = 64, res = TCL_OK, fn;
    uint64_t N = 0, p = 0, r = 0, maxmem = 0;
    size_t out_len;
    Tcl_Obj *resultObj;
    (void) clientData;

    dprintf("Called");

    /* Clear errors */
    Tcl_ResetResult(interp);
    ERR_clear_error();

 *
 * Side effects:
 *	Creates commands
 *
 *-------------------------------------------------------------------
 */
int Tls_KDFCommands(Tcl_Interp *interp) {
    Tcl_CreateObjCommand(interp, "tls::hkdf", KDF_HKDF, (ClientData) NULL, (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateObjCommand(interp, "tls::pbkdf2", KDF_PBKDF2, (ClientData) NULL, (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateObjCommand(interp, "tls::scrypt", KDF_Scrypt, (ClientData) NULL, (Tcl_CmdDeleteProc *) NULL);
    return TCL_OK;
}